The goal of this project is to elucidate the mode of action and cellular pharmacology of broad-spectrum acyclic nucleotide analogs, which have potent activity against the cytopathic effect of HIV virus both in vitro and in vivo. This project is focused on the effects in primary human lymphoid cells of the two leading compounds of this class, 9-(2- phosphonomethoxyethyl) adenine (PMEA) and the related derivative 9-(2- phosphonomethoxypropyl)adenine (PMPA). The specific aims are: 1) To purify and characterize a mitochondrial nucleotide kinase that may be involved in cellular activation of the acyclic phosphonate analogs in human lymphoid cells; 2) To develop antibodies directed against this mitochondrial kinase, to define its specificity for acyclic phosphonate analogs, and study cellular regulation of this route of nucleotide analog metabolism; 3) To evaluate the role of the mitochondrial kinase in the toxicity of the acyclic phosphonate analogs and related nucleotide analogs and address the question whether metabolites of these compounds are compartmentalized within cells, and 4) To evaluate the metabolism and the anti-HIV activity of acyclic phosphonate analogs and other nucleoside inhibitors of reverse transcriptase in primary human monocytes/macrophages, and resting peripheral blood mononuclear cells, which are long-term reservoirs of latent virus in AIDS patients.